This study will focus on high risk behaviors (excessive alcohol use, drug use, physical and/or sexual aggression, and unsafe exit behaviors-e.g., drinking and driving, riding with a drinking driver) of young adults who patronize clubs. These risk behaviors are prevalent in clubs and drinking establishments (see Significance). Our goals are twofold: (1) to develop a screener that accurately assesses a group's level of risk for one specific night of club attendance and based upon this assessment, (2) to provide naturally occurring social groups with the necessary skills to identify vulnerability to these high risk behaviors and to provide them with tools to protect their members against those risks by being prepared to implement the 3 O's: (a) Outreach-approach fellow group members who are at risk, (b) Options-to suggest alternatives that would increase safety and (c) Out-to increase awareness of when it is time to leave. This brief, interactive intervention will be delivered by small tablet computers that utilize mobile application technology and cellular wireless service. This will facilitate later adoption in the real world, in a way to provide a low cost delivery and n a manner that will engage the young adult population. Specific Aim I is designed to test and reduce the number of screening questions necessary to develop a risk algorithm (for our high risk behaviors) for social groups and to test the feasibility of immediate onsite compilation of individual results into a group risk algorithm. A data collection method is used that intercepts participants as they enter and exit a location and links these data, while maintaining anonymity. For Specific Aim 1 a total of 300 groups (n=720 participants) will be given a short survey and biological measures of alcohol and drug use will be collected, while maintaining anonymity for the participants. The survey data will be linked for the group. With Specific Aim II, the brief, group-based intervention is designed and the feasibility tested. With a new sample of 300 groups, randomly assigned to intervention and control conditions, both entrance and exit data collection will include survey data, oral fluid samples (for drug analyses), and breath tests (for alcohol). These data will be compared for the intervention and control groups to determine if the intervention was successful in helping groups to assess their vulnerability for high risk situation inside the club, whether they implemented more actions based upon the skills they learned, and whether the intervention group had fewer high risk behaviors than the control group.